1. Field of the Invention
The present teachings relate to support material formulations, methods for synthesizing same, and their use as supports for catalytically active material, particularly for CO oxidation and lean burn deNOx control.
2. Discussion of the Related Art
Noble metal nanoparticles loaded on nanoporous titania (TiO2) supports are attractive for catalyzing reactions germane to energy generation and environmental preservation, for example, photocatalytic generation of hydrogen from water and carbon monoxide (CO) oxidation. The efficiency of the TiO2 supported catalysts is increased through electronic-structure-level interactions at the support-catalyst metal interface. For example, the amount of CO converted to CO2 per unit mass of Pt catalyst per unit time (referred to as the turnover frequency, hereinafter “TOF”) is hundredfold higher with a TiO2 support than with a SiO2 support over a temperature range of 150 to 550° C. Clearly, the catalyst and support chemistries, the support structure, and the catalyst particle distribution within the pores of the support are all parameters that impact the TOF and should be controlled to increase TOF.
Several techniques have been devised to synthesize catalyst-support composites, such as impregnation, sol-gel based processes, flame spray synthesis, electrodeposition, laser pyrolysis, sonochemistry and UV irradiation. In all of these processes, the support material, typically disordered, is prepared first, followed by the transfer to, or formation of, catalyst particles within the pores of the support material. Such sequential approaches have disadvantages such as pore plugging, insufficient control of catalyst distribution within the pores, and high costs due to production complexity. Disordered and disconnected pores in the support material can lead to increased mass transfer resistance.
There is a need for synthesis routes for supported catalyst that allow for formation of patterned and interconnected porous supports with catalyst nanoparticles of controllable size distributed throughout the support structure.